Learn Mathematics

Welcome to the Submit a Bug Report section of Mathonline. We greatly appreciate users that submit bug reports found on any of our pages, as it helps improve the quality of the content we put out. With there being hundreds of pages on Mathonline, it is very easy for a pesky little bug to appear.

Nevertheless, to help us fix these bugs as quickly as possible, we ask that you please submit bug reports in the following form for organization sake. All posts made that are not about errors on a page on the site will be deleted.

In the "post title", simply write the name of the page that has the error.

In the body of the post, describe what the bug is. Be as brief as possible!

Just after the definition of the closure of a set S, it is stated that in any metric space (M, d), for every set S \subseteq M, S \subset S^{\bar}. However, if we let M be a finite set of cardinality greater than 1 with the discrete topology, the closure of the open ball around any point is the open set itself. Therefore, I believe it should be the case that S \subseteq S^{\bar}.